Point of Mental Retardation

when smoking weed, the point at which one gets so high that he/she resembles somebody with some kind of mental retardation. Characteristics include flailing arms at nothing, yelling/screaming at nothing, profound uncontrollable laughter. there is no specified amount that one has to smoke in order to achieve this state of mind because everyone's tolerance is different. everybody expresses their point of mental retardation differently, but it's usually easy to tell when one has reached the point of mental retardation. in conversation, this phrase is typically abbreviated to 'PMR.'